If screen is showing you the cleaning up message, this points out that Disk cleanup utility is functioning erase all the useless files from the system. These files include temporary, offline, upgrade logs, caches, old files, and so on.

What is cleaning up in Windows Update?

The Windows Update Cleanup feature is designed to help you to regain valuable hard disk space by removing bits and pieces of old Windows updates that are no longer needed.

What does cleaning up mean on Windows 10?

When the screen displays the message of doing cleanup, it means the Disk Cleanup utility is trying to remove unnecessary files for you, including temporary files, offline files, old Windows files, Windows upgrade logs, etc. The whole process will take a long time like several hours.